Lower bead breaker stroke control apparatus

Abstract

In a tire changing machine, an apparatus is provided for controlling the stroke of the lower bead breaker shoe in breaking a tire bead from the bead seat of a wheel which includes a fluid motor and a pivot arm which cooperate to move the lower shoe from an initial position below and radially outwardly spaced from the wheel and tire, along a radially inward path to a position wherein the lower shoe engages the bead of a tire. A regulator assembly connected to the lower shoe prevents further radial inward, pivotal movement of the lower shoe once contact is made with the tire bead, and thereafter permits only upward movement of the lower shoe along a slight angle to the vertical so that it follows the profile of the wheel, without contacting the wheel, for completing the bead breaking operation.

What is claimed is: 
     
       1. In power tire changing machine including a frame carrying a horizontal platform for supporting a wheeel mounting a tire having a lower bead, an apparatus for breaking the lower bead of the tire from the wheel, comprising: a pivot arm pivotally mounted to the frame of the tire changing machine below the wheel and tire carried by the horizontal platform of the frame;   a lower bead breaker shoe pivotally mounted to said pivot arm, said lower bead breaker shoe having an upper end disposed in an initial position below and radially outwardly spaced from the lower bead of the tire;   fluid motor means connected to said lower bead breaker shoe for moving said lower bead breaker shoe with a combined upward and radially inward motion relative to the tire and wheel so that said upper end of said lower bead breaker shoe engages the lower bead of the tire;   regulator means connected to said lower bead breaker shoe for selectively stopping said radially inward movement of said upper end of said lower bead breaker shoe at a predetermined point spaced from the wheel, while permitting continued upward movement of said upper end of said lower bead breaker shoe against the lower bead of the tire without contacting the wheel to break the lower bead of the tire from the wheel.   
     
     
       2. The apparatus of claim 1 in which said regulator means comprises: a fixed regulator plate;   a regulator arm connected to said lower bead breaker shoe, said regulator arm extending between said lower bead breaker shoe and said regulator plate;   means operatively connecting said regulator arm to said regulator plate;   said regulator arm being laterally movable toward said regulator plate in response to said radially inward, pivotal movement of said lower bead breaker shoe, said connecting means being adapted to seat along said regulator plate and engage said regulator arm when said regulator arm moves a predetermined distance toward said regulator plate, said connecting means preventing further lateral movement of said regulator arm after said predetermined distance so as to prevent further pivotal movement of said lower bead breaker shoe.   
     
     
       3. The apparatus of claim 2 in which said regulator arm is formed with a slot at one end, said regulator plate being formed with a surface having a plurality of spaced notches, said slotted end of said regulator arm being disposed along said regulator plate and movable so as to align said slot thereof with said notches in said regulator plate, said connecting means including a bar having a pin at one end, said pin being adapted to seat in each of said notches of said regulator plate and being slidable within said slot in said regulator arm, said regulator arm being laterally movable toward said regulator plate in response to said pivotal movement of said lower bead breaker shoe so that said pin slides within said slot of said regulator arm, said pin engaging the end of said slot in said regulator arm to prevent further lateral movement thereof toward said regulator plate after a predetermined amount of lateral movement, said lower bead breaker shoe being thereafter prevented by said regulator arm from further radially inward, pivotal movement relative to the tire bead. 
     
     
       4. The apparatus of claim 3 in which said surface of said regulator plate is angled so that said notches formed in said regulator plate are disposed at different distances from said lower bead breaker shoe, said regulator arm being permitted to move different lateral distances toward said regulator plate with said pin seated in different notches in said regulator plate so as to vary the amount of radial inward movement of said lower bead breaker shoe to accommodate wheels of different diameter. 
     
     
       5. The apparatus of claim 1 in which said lower bead breaker shoe is formed in a C-shape including a lower end, and an arcuate middle portion between said upper end and said lower end, one end of said pivot arm being pivotally connected to said arcuate middle portion of lower bead breaker shoe, and the other end of said pivot arm being pivotally mounted to the tire changing machine. 
     
     
       6. The apparatus of claim 5 in which said fluid motor means includes a piston mounted to said arcuate middle portion of said lower bead breaker shoe offset from said pivot arm, said piston being movable to pivot said lower bead breaker shoe about the connection thereof to said pivot arm. 
     
     
       7. The apparatus of claim 1 in which said lower bead breaker shoe is formed in a C-shape having a lower end, and an arcuate middle portion between said upper end and said lower end, said regulator means including a regulator arm pivotally mounted to said lower end of said lower bead breaker shoe and a regulator plate spaced from said lower bead breaker shoe, said lower bead breaker shoe being pivoted so as to laterally mcve said regulator arm toward said regulator plate. 
     
     
       8. The apparatus of claim 1 further including a vertical lock-out assembly comprising: a bracket connected to said lower bead breaker shoe, said bracket being movable upwardly with said lower bead breaker shoe;   a pin mounted to said bracket, said pin being movable within a slot having lobes formed in said tire changing machine;   adjustment means for moving said bracket and said pin relative to said slot, said bracket preventing upward movement of said lower bead breaking shoe upon contact of said pin with one of said lobes of said slot.   
     
     
       9. In a power tire changing machine including a frame carrying a horizontal platform for supporting a wheel mounting a tire having a lower bead, an apparatus for breaking the lower bead of the tire from the wheel, comprising: a pivot arm pivotally mounted to the frame of the tire changing machine below the wheel and tire carried by the horizontal platform of the frame;   a lower bead breaker shoe pivotally mounted to said pivot arm, said lower bead breaker shoe having an upper end disposed in an initial position below and radially outwardly space from the lower bead of the tire;   fluid motor means connected to said lower bead breaker shoe for moving said lower bead breaker shoe with a combined upward and radially inward motion relative to the tire and wheel so that said upper end of said lower bead breaker shoe engages the lower bead of the tire;   adjustable regulator means connected to said lower bead breaker shoe for stopping said radially inward movement of said upper end of said lower bead breaker shoe at selected locations relative to the wheel depending upon the diameter of a given wheel so that said upper end of said lower bead breaker shoe is spaced from a wheel of given diameter upon engagement with the lower bead of the tire, while permitting continued upper movement of said upper end of said lower bead breaker shoe against the lower bead of the tire without contacting the wheel to break the lower bead of the tire from the wheel.